Thin layer photonic integrated circuit based optical signal manipulators

Abstract

Integrated optical intensity or phase modulators capable of very low modulation voltage, broad modulation bandwidth, low optical power loss for device insertion, and very small device size are of interest. Such modulators can be of electro-optic or electro-absorption type made of an appropriate electro-optic or electro-absorption material in particular or referred to as an active material in general. An efficient optical waveguide structure for achieving high overlapping between the optical beam mode and the active electro-active region leads to reduced modulation voltage. In an embodiment, ultra-low modulation voltage, high-frequency response, and very compact device size are enabled by a semiconductor modulator device structure, together with an active semiconductor material that is an electro-optic or electro-absorption material, that are appropriately doped with carriers to substantially lower the modulator voltage and still maintain the high frequency response. In another embodiment, an efficient optical coupling structure further enables low optical loss. Various embodiments combined enable the modulator to reach lower voltage, higher frequency, low optical loss, and more compact size than previously possible in the prior arts.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]The present application is the U.S. national stage application of International Application No. PCT / US2014 / 041550, filed Jun. 9, 2014, which application published on Dec. 18, 2014, as WO2014 / 200920, and further claims priority to U.S. Provisional Application No. 61 / 832,940, filed Jun. 9, 2013; U.S. Provisional Application No. 61 / 833,488, filed Jun. 11, 2013; and U.S. Provisional Application No. 61 / 913,945, filed Dec. 10, 2013, the contents of which are incorporated herein by reference in their entireties.BACKGROUND[0002]The present invention relates to semiconductor photonic, discrete optic, integrated optic, and opto-electronic devices. In particular, the present invention relates to integrated optical modulators capable of modulation of the light beam intensity or phase by an electrical signal. Such modulators are required for converting electrical signals into optical signals so that the light beam can be used to transmit information ...

AI Technical Summary

Benefits of technology

[0035]It is an aim of the present invention to provide compact intensity or phase modulators with very low switching voltage, high modulation bandwidth, low optical loss, short modulator device length, high optical saturation intensity, resulting in intensity or phase modulators with exceedingly high modulator relative figure of merit that is generally over 10 times to 1,000 times higher than the modulators based on prior arts.

[0078]In as yet another aspect of the present invention, the waveguiding structure tapers down to a width smaller than a wavelength in the waveguiding material so as to strongly push the mode away from the lower transparent waveguiding structure towards the quantum wells or bulk material, thereby increasing the optical mode energy overlapping with the quantum wells or bulk material.

Problems solved by technology

Normally, such thin waveguiding layer can increase the device insertion loss as it is hard to couple light into the layer optically, especially from an optical fiber.

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